From 0416e5670d4991b2846d732b8bb12c3844b17b45 Mon Sep 17 00:00:00 2001
From: Tal Aloni <tal.aloni.il@gmail.com>
Date: Sat, 20 May 2023 00:57:05 +0300
Subject: [PATCH] NTLMCryptography: Add .NET 5.0 \ 6.0 support

---
 .../NTLM/NTLMAuthenticationTests.cs           | 12 ++++++-
 .../NTLM/Helpers/NTLMCryptography.cs          | 31 +++++++++++++++----
 2 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/SMBLibrary.Tests/NTLM/NTLMAuthenticationTests.cs b/SMBLibrary.Tests/NTLM/NTLMAuthenticationTests.cs
index 224da07..a96979d 100644
--- a/SMBLibrary.Tests/NTLM/NTLMAuthenticationTests.cs
+++ b/SMBLibrary.Tests/NTLM/NTLMAuthenticationTests.cs
@@ -1,4 +1,4 @@
-/* Copyright (C) 2014-2019 Tal Aloni <tal.aloni.il@gmail.com>. All rights reserved.
+/* Copyright (C) 2014-2023 Tal Aloni <tal.aloni.il@gmail.com>. All rights reserved.
  * 
  * You can redistribute this program and/or modify it under the terms of
  * the GNU Lesser Public License as published by the Free Software Foundation,
@@ -27,6 +27,15 @@ namespace SMBLibrary.Tests
             Assert.IsTrue(ByteUtils.AreByteArraysEqual(hash, expected));
         }
 
+        // Will use weak DES key
+        [TestMethod]
+        public void LMv1HashTestEmptyPassword()
+        {
+            byte[] hash = NTLMCryptography.LMOWFv1("");
+            byte[] expected = new byte[] { 0xaa, 0xd3, 0xb4, 0x35, 0xb5, 0x14, 0x04, 0xee, 0xaa, 0xd3, 0xb4, 0x35, 0xb5, 0x14, 0x04, 0xee };
+            Assert.IsTrue(ByteUtils.AreByteArraysEqual(hash, expected));
+        }
+
         [TestMethod]
         public void NTv1HashTest()
         {
@@ -155,6 +164,7 @@ namespace SMBLibrary.Tests
         public void TestAll()
         {
             LMv1HashTest();
+            LMv1HashTestEmptyPassword();
             NTv1HashTest();
             NTv2HashTest();
             LMv1ResponseTest();
diff --git a/SMBLibrary/Authentication/NTLM/Helpers/NTLMCryptography.cs b/SMBLibrary/Authentication/NTLM/Helpers/NTLMCryptography.cs
index 5dcdc2e..0754520 100644
--- a/SMBLibrary/Authentication/NTLM/Helpers/NTLMCryptography.cs
+++ b/SMBLibrary/Authentication/NTLM/Helpers/NTLMCryptography.cs
@@ -1,4 +1,4 @@
-/* Copyright (C) 2014-2017 Tal Aloni <tal.aloni.il@gmail.com>. All rights reserved.
+/* Copyright (C) 2014-2023 Tal Aloni <tal.aloni.il@gmail.com>. All rights reserved.
  * 
  * You can redistribute this program and/or modify it under the terms of
  * the GNU Lesser Public License as published by the Free Software Foundation,
@@ -78,11 +78,26 @@ namespace SMBLibrary.Authentication.NTLM
         {
             DES des = DES.Create();
             des.Mode = mode;
-            DESCryptoServiceProvider sm = des as DESCryptoServiceProvider;
-            MethodInfo mi = sm.GetType().GetMethod("_NewEncryptor", BindingFlags.NonPublic | BindingFlags.Instance);
-            object[] Par = { rgbKey, mode, rgbIV, sm.FeedbackSize, 0 };
-            ICryptoTransform trans = mi.Invoke(sm, Par) as ICryptoTransform;
-            return trans;
+            ICryptoTransform transform;
+            if (DES.IsWeakKey(rgbKey) || DES.IsSemiWeakKey(rgbKey))            
+            {
+#if NETSTANDARD2_0
+                MethodInfo getTransformCoreMethodInfo = des.GetType().GetMethod("CreateTransformCore", BindingFlags.NonPublic | BindingFlags.Static);
+                object[] getTransformCoreParameters = { mode, des.Padding, rgbKey, rgbIV, des.BlockSize / 8 , des.FeedbackSize / 8,  des.BlockSize / 8, true };
+                transform = getTransformCoreMethodInfo.Invoke(null, getTransformCoreParameters) as ICryptoTransform;
+#else
+                DESCryptoServiceProvider desServiceProvider = des as DESCryptoServiceProvider;
+                MethodInfo newEncryptorMethodInfo = desServiceProvider.GetType().GetMethod("_NewEncryptor", BindingFlags.NonPublic | BindingFlags.Instance);
+                object[] encryptorParameters = { rgbKey, mode, rgbIV, desServiceProvider.FeedbackSize, 0 };
+                transform = newEncryptorMethodInfo.Invoke(desServiceProvider, encryptorParameters) as ICryptoTransform;
+#endif
+            }
+            else
+            {
+                transform = des.CreateEncryptor(rgbKey, rgbIV);
+            }
+
+            return transform;
         }
 
         /// <summary>
@@ -123,7 +138,11 @@ namespace SMBLibrary.Authentication.NTLM
 
         public static Encoding GetOEMEncoding()
         {
+#if NETSTANDARD2_0
+            return ASCIIEncoding.GetEncoding(28591);
+#else
             return Encoding.GetEncoding(CultureInfo.CurrentCulture.TextInfo.OEMCodePage);
+#endif
         }
 
         /// <summary>